Virtualization method for an access network system and its management architecture

ABSTRACT

A method for control an access network node which is comprising of central office (CO) and more than one customer premises equipment (CPE), provides a single management interface in the CO to a software defined network management system, that utilizes a software defined network protocol, the interface allows the software defined network management system to configure an user flow in the access network node by assigning a network node interface resides in the CO which interconnects to a core network and an user network node interface resides in the CPE which interconnects to a user terminal and a required user data forwarding function for the flow, the access network node maintains its own forwarding resources and it determines available resources required for the forwarding request, configures the CO and/or the CPE with a protocol translation which adapts the software defined protocol with the legacy protocol when the CO and/or the CPE works with the legacy protocol.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority benefit of U.S. Provisional Application No. 62/032,578, filed on Aug. 3, 2014 by inventor Toshihiko Kusano

FIELD OF THE INVENTION

The present invention relates to a network virtualization method for a telecommunication network system which comprise of SDN non-native devices to manage them seamlessly among with SDN native devices from a SDN Management System.

The present invention is particularity suitable for an access network system which is comprised from Central Office (CO) and Customer Premises Equipment (CPE).

BACKGROUND OF THE INVENTION

Recently, Software Defined Network (SDN) has been widely recognized as the next generation network management scheme in the packetized data communication era. Current SDN defines SDN native control message and protocol, OpenFlow is the well-known standard for the control message, but it may not be true to determine the protocol is the only choice applicable to the SDN concept. Hereinafter use “SDN control message” as a generalized protocol name which can be used for SDN.

In the origin of the OpenFlow, it has been assumed to control a standalone OpenFlow device which will replace today's Layer two (2) switches (L2SW) and routers; all of them are not in a form of multi node system. Compare with the L2SWs and routers, access network system is comprised of CO and CPEs and they are tightly coupled in its configuration. For example, Passive Optical Network (PON) which is used for Fiber To The X (FTTX, X stands various types of delivery method) services consists from Optical Line Terminator (OLT) as CO device and Optical Network Unit (ONU) as CPE device. The OLT controls the ONUs with a specific control method and protocol, which is known as Multi-Point Control Protocol (MPCP) and Operation Administration and Maintenance (OAM) protocol. If operator wants to apply the current OpenFlow control to those devices, both the OLT and ONU need to be an OpenFlow native device.

While network operator deployed the access system in large, it is a significant disadvantage for operators who wants to use OpenFlow because all standalone device needs to be a standalone SDN native device. The situation will enforce operators to replace the whole access network system if they plan to manage devices under integrated SDN management. Current resolution requests to replace whole CPEs in the customer sites; such construction will cause a severe service disruption. On the other hand, when operator decides to manage using SDN across the network system includes the access system, it is essential to manage every system in an integrated manner for maximize the benefit from the view of OPEX and CAPEX for the network management.

From this background, it is proposed to virtualize an access network system itself as a single SDN native node, and thereinafter, the SDN Management System can control and manage the access system without a necessity to aware the type of device but control and manage them as a part of the SDN device.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention is to support virtualized SDN adapted access network which can be controlled by SDN Management System as same as a SDN native device.

According to the present invention, there is provided a telecommunication network system comprising of; a SDN Management System, Virtual Access Node comprise a Central Office (CO) and a Customer Premises Equipment (CPE), user terminals, core data network, and virtualized access User Network Interface (UNI) and virtualized access Network Node Interface (NNI). Data channels which carry user data packets across the network; i.e., among access network system (between CO and CPE), user terminals, and core data network. Virtualized access UNI and virtualized access NNI interfaces between use terminal and core data network respectively. From the SDN Management System, it can control the Virtual Access Node as a single device which has two interfaces for downstream side (virtualized access UNI) and upstream side (virtualized access NNI), and control the virtual device without knowing its internal structure.

The present invention consists from; a) a concept of a Virtual Access Node which comprises SDN non-native CO and CPEs, b) a mechanism to convert multi-device structure of an access network into single virtualized node, and c) method to co-exist SDN non-native CO/CPEs and SDN native CO/CPEs for potential configuration in the future.

Following previously filed two patents have supportive role to the current patent; PCT/IL13/050947 entitled “TELECOMMUNICATION NETWORK NODE SUPPORTING HYBRID MANAGEMENT USING A HARDWARE ABSTRACTION AND MANAGEMENT PROTOCOL CROSS-CONNECT FUNCTION” claims the control message cross-connect function in the CO to deliver the OpenFlow message to legacy CPEs, and U.S. patent Ser. No. 14/256,011 entitled “ARCHITECTURE FOR AN ACCESS NETWORK SYSTEM MANAGEMENT PROTOCOL CONTROL UNDER HETEROGENEOUS NETWORK MANAGEMENT ENVIRONMENT” claims message bridging and encapsulation function which is an element to realize the current patent.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described in further details with reference to the accompanying drawings, in which;

FIG. 1 is a block diagram of an access network system incorporating with CO and CPE, and the Virtual Access Node with the concept of virtualized UNI and NNI of the present invention;

FIG. 2 is a schematic block diagram of an access network system for a CO and a CPE, that the CO deploys SDN Agent, Resource Manager with two databases for Capability List and Serving Resource List, Protocol Translator, Message Parser for communicating between CO and CPE through a control channel between CO and CPE;

FIG. 3 is a logical representation of a database for the Capability List which shows available functions in the CO and the CPE respectively;

FIG. 4 is a logical representation of a database for the Serving Resource List, which shows a usage status of each resource allocated to complete the requested configuration from SDN Management System;

FIG. 5 is a block diagram of an access network system with SDN native CPE;

FIG. 6 is a block diagram of an access network system both with SDN non-native CPE and SDN native CPE.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, a Virtual Access Node 120 which comprises of CO 101 and CPEs 110. The CO 101 of the Virtual Access Node 120 connects to SDN Management System 130 through a communication network. SDN Management System 130 controls the Virtual Access Node 120 as a single network node and the SDN Management System 120 understands virtualized access UNI 111 and virtualized access NNI 112 as the interface points of the virtualized access node 120 to inter-connecting with outside of the system such as user terminals 140 and core data network 141 to send and receive user data packets for the service data transmission. The SDN Management System 130 can control multiple virtualized access nodes through the communication network.

FIG. 2 describes function blocks in the Virtual Access Node 220 of the current patent. A SDN Agent 202 in the CO 201 interacts with SDN Management System 230 to send and receive SDN control messages. A Resource Manager 203 manages existing feature set in the CO 201 and CPE 210, it is outside of the patent though it is a general understanding that the existing feature set can be confirmed by knowing manufacture and product number etc., that are regularly be able to collect via digital data as an attribute of a managed object. A Resource Manager 203 allocates appropriate resources to complete the flow forwarding request received from a SDN Management System 230 via SDN Agent 202 and it updates the usage status after made an allocation. A Protocol Translator 206 translates a SDN control message to a SDN no-native (legacy) protocol used in the Virtual Access Node 220, hence vast majority of today's deployed access system supports only the legacy protocol then translate a SDN control message to a corresponding legacy message is mandatory. A message parser 207 forwards the legacy protocol translated from SDN control messages to the corresponding flow forwarding resources (hardware resources) in the CO 201 and CPE 210. If the request needs to be forwarded to CPE 210, then the message will be passed to the send/receive socket to transfer via control channel 209 to the target CPE 210. By receiving the message through control channel at CPE 210, the message is passed to the processor 211 through message parser 212 in the CPE 210 and the processor 210 determines the required actions to control its flow forwarding resources 213.

The DN Management System 230 sends a configuration request to the Virtual Access Node 220, the message is comprised of following elements as a minimum set of attributes but not limited;

Virtualized access UNI

Virtualized access NNI

Forwarding action(s) requested

Forwarding action(s) will be varied by system however it is assumed that following types of operation will be generally available;

Packet reception/discarding rule

VLAN manipulation (add/drop/transparent/swap etc.)

Queue configuration

Rate control, shaping and policing

A SDN Agent 202 in the CO 201 receives the request from SDN Management System 230. Since the message designates the virtualized access UNI 111 in FIG. 1 and virtualized access NNI 112 in FIG. 1 as the Virtual Access Node 220 of its termination points and the action does not designate which resource (i.e., CO 201 and/or CPE 210 etc.) then the message is needed to be broken into pieces to be understood by the access network system 220. To resolve which resource(s) to be served for the requested action(s), the SDN Agent 202 passes the message to the Resource Manager 203 to request to allocate appropriate resource(s) and inform the allocation result to the SDN agent 202 to create a corresponding set of messages.

The Resource Manager 203 manages two databases, the one is the Capability List 204 which is shown in FIG. 3 and another is the Serving Resource List 205 which is shown in FIG. 4 respectively.

FIG. 3 is a Capability List 300 of CO 201 and CPE 210 both in FIG. 2 which shows available traffic control feature set in each device. The Capability List consists of columns: Resource ID (Res. ID) 301, features of CPE 310, which is broken into each functions 311, and features of CO 320, which is broken into each functions 321. The feature set 311, 321 can be a greatest set of possible available at CPE and CO devices. The listed feature names 311, 321 in FIG. 3 are defined in IEEE 1904.1™ Standard for Service Interoperability in Ethernet Passive Optical Networks (SIEPON) specification published from The Institute of Electrical and Electronics Engineers, Inc. (IEEE) as an example but it can be defined uniquely by a system depend on its supported feature and operator's requirement. SIEPON specification defines functional blocks as following (defined in section 6.2.1.1 of the specification);

Input block;

Classifier block;

Modifier block;

Policer/Shaper block;

CrossConnect block;

Queues block;

Scheduler block; and

Output block.

For the traffic forwarding perspective, Classifier, Modifier, Policer/Shaper, Queue, and Scheduler contribute major roles in the above listed, and then utilize them as the function set to be managed in the Capability List in FIG. 3.

A column Res. ID 301 in the table in FIG. 3 shows a combination of resources of CO 201 and CPE 210 in FIG. 2; the Virtual Access Node 220 has a multi-branch topology among CO 201 and CPE 210. Res. Id. 1-1 stands a combination of CPE #1 is connecting to the interface #1 of the CO, J-N stands a combination of CPE #N is connecting to the interface #J of CO as well. Cross point of each matrix shows a support status of the function in the corresponding device. If marked as “Supported”, the function is supported and functional by the device while marked as “Not Supported”, the function is neither exist, available, nor enabled.

The Capability List 300 also provides number of resources as a part of capability information. After each remark of Supported, there is a suffix numbering that is presenting existing resources to be used. “Supported 1 (an example is the cross point of Res. ID 1-1 and CPE Classifier)” means the function has one resource and “Supported 10 (an example is the cross point of Res. ID 1-1 and CO Classifier)” means the function has ten resources. The information will be used when determining a new service flow can be admitted to establish or not.

Note that the Capability List 300 should not be limited to the shown function set in the FIG. 3, however it can be varied and extensible or reduced by access technology in use.

The Resource Manager 203 in FIG. 2 identifies which device, either CPE and/or CO, has capabilities to complete the request from SDN management system 230. Analogy of the determination of the resource(s) to serve for the requested function is a system matter, and then the selection algorithm is outside from this patent.

Once the Resource Manager 203 made a decision for the resource to serve the request, the Resource Manager 203 updates the Serving Resource List 400 which is shown in FIG. 4. The Serving Resource List 400 shows which capabilities are used for flow basis. Since the SDN Management System 230 has no visibility of which resources are actually used inside of the CO 201, the CPE 210, nor Virtual Access Node 220, the virtual Access Node 220 needs to maintain the resource usage by its own.

There are two example flows in the Serving Resource List 400 in the FIG. 4. They are Flow ID 1 and Flow ID 2 as shown in Flow ID 402. Listed functions 411, 421 for CPE 410 and CO 420 respectively in the Serving Resource List 400 are corresponding with those in the Capability List 300. In the Serving Resource List 400, each function is noted either “Use”, “No use” for available flows where the function exists. When specific feature is not supported in the Capability List 300, the usage status must be “NA (Not Available)” in the Serving Resource List 400. Therefore, the Resource Manager 203 can identify that classifier and modifier in the CPE #1 have been used and Policer/shaper and scheduler in the interface #1 of the CO have been used.

With understanding number of existing resources of each function in the Capability List 300, it is possible to know whether there is an available resource to be used for new Flow request. Here is an example; Res. ID 1-1 has one CPE Classifier as the resource of CPE #1, and the resource has been used for Flow #1 from the Serving Resource List 400. Then, there is no more resource to be served for new Flow within CPE #1 if requested. Therefore when the SDN Management System 230 request the Virtual Access Node 220 to create a new Flow #X passing through CPE #1 which requires the Classifier in the CPE #1, the request will be rejected. The same mechanism and judgment is true for the CO case. And the Flow establishment will be examined by checking full set of the required feature set is whether exists and available.

The Resource Manager 203 informs to the SDN Agent 201 for which resources are capable and available to complete the requested action from the SDN management system 230 when the Resource Manager determines the request is accepted.

By receiving the resource information from the Resource Manager 203, the SDN Agent 201 generates a set of messages to control each resource independently both in the CO 201 and the CPE 210. The SDN Agent 201 forwards the control messages to the Protocol Translator 206 which translates a SDN control message set to a legacy control message set which is used by the access network system 220. The SDN Agent has a knowledge base which maintains a relationship between SDN control message used with SDN Management System 230 and legacy control message used to control CO 201 and CPE 210 resources internally in the access network system 220. The relation does not have to be one to one but it can be one to many or many to one, the translation rule will be varied by the access network system and the translation rule itself is out of the scope from this patent. When CO and CPE are SDN native devices however their message set has a different arrangement with the SDN message used by SDN manager 230, the knowledge base can be expand to maintain the translation and mapping between those two sets of SDN control message.

The Protocol Translator 206 determines a Destination Address (DA) to each control message. Examples of the DA are IP address, MAC address, Logical Link Id, device Id which is identical to find a corresponding CO and/or CPE. Then assembled control messages are forwarded to the Message Parser 207.

The Message Parser 207 identifies address information in the message header which is usually defined as Destination Address (DA) and forwards each legacy control message to the resource in the CO 201 or forwards it to the CPE 210 through the control channel 209. When CPE 210 receives the legacy control message through the control channel 209, the Message Parser 212 in the CPE 210 redirects the control message to the Processor 211 in the CPE 210 to interpret the request. The Processor 211 configures own flow forwarding resource 213 and replies an acknowledgement if it's the protocol.

FIG. 5 shows a use case that SDN CPE 510 supports native SDN control message processing capability in the SDN module 511 which is attached on top of the CPE 510 which is relevant to the CPE discussed as the CPE 210 in the FIG. 2. This use case is discussed in industry groups such that European Telecommunications Standards Institute (ETSI) and Broadband Forum (BBF). ETSI GS NFV 001 V1.1.1 (2013-10) is publicly available and it is discussing the SDN native CPE in the “Use Case #9: Fixed Access Network Functions Virtualisation” in the Section 13. With regards to the proposed configuration of the paper, this patent can adapt in following two manners.

-   -   (a) The first case is to handle CO 501 and CPE 510 as standalone         SDN native devices. The Resource Manager 203 in the FIG. 2 has         no role to allocate resource(s) to complete the request from the         SDN Management System 530; it means that the SDN Management         System 530 knows an exact SDN control message(s) to configure         each device. By receiving the SDN control message from the SDN         Management System 530 at CO 501, the Resource Manager 203 will         simply update the usage status in the Serving Resource List 205         based on the request.     -   (b) The second case is an access network is virtualized as a         single SDN node 520 and SDN Management System 530 only         identifies the node but not each CO 501 nor CPE 510. In this         case it is assumed that the SDN control message is targeted to         control an abstracted function but not control the exact         application interface of each device. The SDN Agent 202 in the         FIG. 2 understands the SDN controller sends a SDN message to         configure the Virtual Access Node 520, and then request the         Resource Manager 203 to allocate a resource(s). After the         resource allocation, as same as the case to control legacy         system, the SDN Agent 202 generates a set of SDN control         messages to control each CO 501 and CPE 510 individually. Once         the set of SDN messages for each device is generated, there is         no need to translate the SDN control message to a legacy control         message. And then, the SDN Agent forwards the control messages         to the message parser 207 directly, and it then forwards the         messages to the each of flow forwarding resource.

SDN control message such as OpenFlow is defined as a protocol being used in the layer three (3); i.e., network layer. In both cases discussed in [0035], at the time of forwarding a SDN control message to a CPE via a CO, there is a possibility that the SDN control message needs to be forwarded in the layer two (2); i.e., datalink layer, but not in the layer three (3). Since the SDN control message is defined as the layer three message, forward it in the layer two requests the layer three message to be encapsulated in the layer two message. Patent filed as Ser. No. 14/256,011 entitled “ARCHITECTURE FOR AN ACCESS NETWORK SYSTEM MANAGEMENT PROTOCOL CONTROL UNDER HETEROGENEOUS NETWORK MANAGEMENT ENVIRONMENT” invented by Toshihiko Kusano has already proposed a solution for the encapsulation.

FIG. 6 shows a use case with mixed configuration both of SDN non-native CPE 610 and SDN native CPE 611 in the Virtual Access Node 620, they exist simultaneously under the same CO 601. In this use case, both CPEs can be managed seamlessly from the SDN Management System 630 with utilizing the mechanism discussed in this patent. 

What is claimed is:
 1. A method of virtualize an access network node which comprises a Central Office device (CO) and more than one Customer Premises End device (CPE), communicating between CO and CPE using a control channel for controlling purpose, comprising; a virtualized access User Network Interface (UNI) at the interface point of the CPE and user terminal, a virtualized access Network Node Interface (NNI) at the interface point of the CO and core data network, a virtual access node which has interfacing points consist of the virtualized access UNI and virtualized access NNI, a virtual access node which function set is determined by underlying CO and CPE, a SDN Agent resides inside of the CO which communicates with SDN Management System to send and receive SDN control message, and generate partitioned SDN control message which adapt with flow forwarding resources both in CO device and CPE device to configure the resources, a Resource Manager resides inside of the CO which maintains Capability List database and Serving Resource List database, a Protocol Translator resides inside of the CO which translates between SDN control message and legacy control message, and a Message Parser resides inside of the CO which determines the resource to deliver a control message and forward the control message.
 2. The method of claim 1 wherein said a SDN Agent comprising of functions that are ability to; communicate with SDN Management System which controls the virtual access node, request the Resource Manager to allocate resources by forwarding the control message, receive a resource allocation result from the Resource Manager, while both the CO and the CPE are SDN native, then partitions the SDN control message received from SDN Management System into CO and/or CPE oriented SDN control messages to configure flow forwarding resources reside in CO and/or CPE, and forward the SDN control messages to the Message Parser, and while either CO and the CPE are non-SDN native, then forward the message to the Protocol Translator, and receive a reply message(s) and/or acknowledge for the control messages from Protocol Translator and Message Parser
 3. The method of claim 1 wherein said a Resource Manager comprising of functions that are ability to; maintain databases; Capability List and Serving Resource List, while the Capability List will be generated when identifying a capability of devices, CO will be identified at the time of boot up, and CPEs will be identified when the device is registered at the hosting CO, while the skeleton of the Serving Resource List will be generated in the same time of the Capability List is generated and every time the Resource Manager updates when allocates and deallocates resources for each Flow, evaluate available resource(s) in the CO and/or the CPE to complete a request received from the SDN Agent by lookup the Capability List and Serving Resource List, and allocate appropriate resource(s) when available to configure the requested forwarding.
 4. The method of claim 1 wherein said a Message Translator comprising of functions that are ability to; translate between SDN control message and legacy control message which is used by the CO and the CPE, and add a proper message header with destination address for the legacy control message
 5. The method of claim 1 wherein said a Message Parser which delivers control message to the corresponding flow forwarding resource in the CO and/or the CPE received from both the SDN Agent and the Protocol Translator, and forwards acknowledgement to the SDN Agent or the Protocol Translator based on the message type; a SDN message is to the SDN Agent and a legacy protocol to the Protocol Translator, respectively. 